Quaternary ammonium compounds have been widely used as bactericides, algicides and molluscicides to treat circulating or static bodies of water. The estimated current market for quaternary ammonium compounds in the water treatment of cooling towers, pool, and spa industries is approximately 15 to 16 million pounds per year. These markets have been traditionally served by higher alkyl and dialkyl quaternary ammonium compounds as it is known that such compounds possess potent biocidal properties.
Higher alkyl and dialkyl quaternary ammonium compounds known in the art, however, suffer from one or more deficiencies which include a limited spectrum of biocidal activity, high foaming characteristics, inherent toxicity, and disagreeable odor production. Moreover, it is known that the beneficial biocidal effects of these agents are substantially inhibited when used in hard water. Hence, the aforementioned deficiencies are important factors in limiting the greater usage of quaternaries as biocides in practical water treatment.
For example, dioctyldimethylammonium chloride has low foam, but has high toxicity and poor bactericidal and algicidal properties. Didecyldimethylammonium chloride, in contrast, is a highly effective bactericide and algicide with low toxicity, but has high foam. Similarly, diisodecyldimethyl ammonium chloride disclosed in U.S. Pat. Nos. 4,444,790 and 4,450,174 causes eye irritation and odor problems. The high foaming characteristic of conventional dialkyl quaternaries is an undesirable feature in their use as algicides in recirculating cooling water systems.
Various quaternary ammonium compounds, including dioctyldimethylammonium chloride, have been used as molluscicides for controlling molluscs, e.g. zebra mussels and asian clams, infestation of fresh water supplies (see, for example, U.S. Pat. No. 5,015,395 and references therein). However, many of these quaternaries suffer from at least one of the aforementioned deficiencies and thus do not offer an effective means for controlling mollusc growth.
Zebra mussels (Dreissena polymorpha) have recently been discovered in various lakes and rivers of the Midwest and Northeast regions of the United States. For example, Zebra mussel contamination was found in the Great Lakes of North America which serve as the main fresh water supply for domestic municipal, utility, and industrial use in this region. The resulting economic costs to industry and fishing in this region alone was estimated to be about $500 million in 1990.
Because of their propensity to reproduce quickly and their ability to affix themselves onto any hard surface in contact with an aqueous system in which they are present, zebra mussels are particularly troublesome in municipal water treatment plants and industrial water systems as zebra mussels can foul water intake piping and process equipment. Accordingly, there is a need for safe and effective molluscicides for practical water treatment to inhibit zebra mussel growth.
Surprisingly, it has now been discovered that decylnonyl- and decylisononyldimethylammonium compounds, especially decylnonyldimethylammonium chloride and decylisononyldimethylammonium chloride, exhibit a superior range of bactericidal, algicidal, and molluscicidal properties with virtually none of the undesirable foaming properties and toxicities commonly found in quaternary ammonium compounds currently in use. In particular, the quaternary ammonium compounds of the invention are especially effective in inhibiting the growth of algae such as Chlorella pyrenoidosa, Mustard Algae and Phormidium luridum.
Decylnonyldimethylammonium chloride and decylisononyldimethylammonium chloride, individually or as mixtures thereof, therefore, have enormous potential utility in the treatment of pools, spas, and recirculating and stationary cooling towers as well as in household disinfectant products and other industrial biocide market areas.